Don`t work with "http://google.co.jp"

Don't work!
Try - domain_name("www.xakep.ru")

Traceback (most recent call last):
1: from main.rb:5:in <main>' main.rb:2:in domain_name': undefined method `split' for nil:NilClass (NoMethodError)

It got marked as Best Practices, but here the idea is to solve it yourself instead of using libraries...

This is great. I didn't know about URI.parse or that #last could take an argument! Thanks

You really need a better definition of "domain name" for that case. When the entire specification is a set of test cases, everything else is undefined behavior.

I like this one-line solution. I find this olution clever, but not a best practice.

With http://www.zombie-bites.com.cn don't work

Im getting better, I did the same!

Thanks. Reading about it now.

Can someone explain this solution to me? My solution is fine, but could use some refactoring, so I was wondering how this solution works - particularly how the regexp works here. Thanks.

Thanks AJFarmer for the heads up.

Not really, just simpler to read and write.